The present invention relates to a handle which is to be secured to a portable drill and which comprises a dust suction device with its suction inlet surrounding the drilling region to prevent the dust and shavings produced during the use of the drill from being dispersed into the environment. The known art includes proposals for various suction devices to be applied to portable drills to remove, through suitable heads, the dust formed directly adjacent to the drilling point.
For example, U.S. Pat. No. 3,850,254 describes a suction device whose rotor is caused to rotate, through a suitable coupling mechanism, directly by the motor rotating the drill arbor. This solution, however, has the disadvantage of low efficiency, owing to the fact that in modern drills the speed of rotation of the arbor is continuously variable over a wide range of values to enable the most diverse types of materials to be drilled, and that consequently the suction device does not always operate at its optimal speed. Furthermore, the casing of the suction device is not shaped to form a handle facilitating the use of the tool, and its overall dimensions are large.
Suction devices comprising a gripping projection to hold the tool firmly have also been proposed, for example as described in U.S. Pats. Nos. 4,097,176 and 4,207,953. In such cases the suction unit is a separate component connected to the said handle and with the suction head positioned in the vicinity of the point to be drilled by means of a flexible duct. This compromises the maneuverability and practicality of operation of the assembly.